Investigating a novel Asgard archaeon and its tubulin-like proteins
type: CreativeWork
description: Since their discovery in 2015, the Asgard Archaea have been redefining our understanding of the origin of the eukaryotic cell. Metagenome-assembled-genomes (MAGs) from various marine environments have shown that this kingdom, officially called Promethearchaeati, encodes many Eukaryotic Signature Proteins (ESPs); proteins that were once thought to be unique but ubiquitous to eukaryotic cells. The presence of ESPs in the Asgard Archaea has challenged the definition of a eukaryote, suggesting that certain ‘eukaryotic-specific’ systems, such as a complex cytoskeleton, may have originated prior to eukaryogenesis (the evolutionary process that gave rise to the Last Eukaryotic Common Ancestor (LECA)). Phylogenetic analyses of the many Asgard archaeal MAGs that have become available suggest a strong affiliation between Asgard Archaea and Eukarya, either as sister lineages or with Eukarya emerging from within the Asgard Archaea phylum, making these Archaea essential for studying the origin of eukaryotes. Moreover, the cytoskeleton is a vital, dynamic network of proteins that regulates cell structure, shape, and division, and our evolutionary understanding of the transition from the prokaryotic to the eukaryotic cytoskeleton remains incomplete. The phenotypic characterisation of the Asgard Archaea and validation of the existence of a eukaryotic-like cytoskeleton has been hampered by the difficulty of culturing and isolating these organisms. To date, only three Asgard archaeal enrichments have been published: Promethearchaeum syntrophicum MK-D1, Candidatus Lokiarchaeum ossiferum B35, and Ca. Harpocratesius repetitus FW102, all of which have been unable to be isolated but are maintained in co-culture with other organisms. This inability to isolate pure cultures has hampered research; therefore, in vitro techniques have been used to biochemically characterise cytoskeletal proteins identified in their genomes. Examples of these proteins include the Asgard actin homologue, lokiact…
abstract: Since their discovery in 2015, the Asgard Archaea have been redefining our understanding of the origin of the eukaryotic cell. Metagenome-assembled-genomes (MAGs) from various marine environments have shown that this kingdom, officially called Promethearchaeati, encodes many Eukaryotic Signature Proteins (ESPs); proteins that were once thought to be unique but ubiquitous to eukaryotic cells. The presence of ESPs in the Asgard Archaea has challenged the definition of a eukaryote, suggesting that certain ‘eukaryotic-specific’ systems, such as a complex cytoskeleton, may have originated prior to eukaryogenesis (the evolutionary process that gave rise to the Last Eukaryotic Common Ancestor (LECA)). Phylogenetic analyses of the many Asgard archaeal MAGs that have become available suggest a strong affiliation between Asgard Archaea and Eukarya, either as sister lineages or with Eukarya emerging from within the Asgard Archaea phylum, making these Archaea essential for studying the origin of eukaryotes. Moreover, the cytoskeleton is a vital, dynamic network of proteins that regulates cell structure, shape, and division, and our evolutionary understanding of the transition from the prokaryotic to the eukaryotic cytoskeleton remains incomplete. The phenotypic characterisation of the Asgard Archaea and validation of the existence of a eukaryotic-like cytoskeleton has been hampered by the difficulty of culturing and isolating these organisms. To date, only three Asgard archaeal enrichments have been published: Promethearchaeum syntrophicum MK-D1, Candidatus Lokiarchaeum ossiferum B35, and Ca. Harpocratesius repetitus FW102, all of which have been unable to be isolated but are maintained in co-culture with other organisms. This inability to isolate pure cultures has hampered research; therefore, in vitro techniques have been used to biochemically characterise cytoskeletal proteins identified in their genomes. Examples of these proteins include the Asgard actin homologue, lokiact…
author: Nobs, Stephanie Jane
keywords: archaea, eukaryogenesis, microbial evolution, tubulin, anzsrc-for: 310199 Biochemistry and cell biology not elsewhere classified, anzsrc-for: 310799 Microbiology not elsewhere classified, anzsrc-for: 310299 Bioinformatics and computational biology not elsewhere classified
license: http://purl.org/coar/access_right/c_f1cf
license: https://creativecommons.org/licenses/by/4.0/
date published: 2026
date modified: 2026-07-24T05:34:32Z
provider: University of New South Wales
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: UNSW, Sydney

PropertyValue
property ID: Handle
value: http://hdl.handle.net/1959.4/108157

PropertyValue
property ID: DOI
value: 10.26190/unsworks/32453